Men in motion

by Karen Moltenbrey

To achieve more realistic animation in games, developers have been using standard motion-capture techniques to create unique, compelling character movements. Links DigiWorks of Tokyo, however, has taken motion capture in games much further-six times, in fact-while creating an opening cinematic sequence involving six characters for Capcom's upcoming Onimusha: Warlords game, expected to be released this month, for the PlayStation 2 console.

Using a Vicon 8 system from Oxford Metrics, Links DigiWorks simultaneously captured the motions of six actors for integration into samurai battle sequences that appear in the cinematic. "With the Vicon 8, which was introduced last year, we are no longer limited to capturing the motion of just one person at a time," says Koji Ichihashi, president of Links DigiWorks. "Previously, when we needed two or three people in a battle scene, we'd have to capture the motion of each one separately, and then try to match them up in a scene. By shooting all the movement at one time, the actions and reactions of the actors during a fight scenario remain natural, fluid, and realistic."

Onimusha's opening cinematic sets the stage for the game's story line, depicting agile warriors battling to the death on behalf of their powerful, fearsome warlords during 1560 feudal Japan. The video console game, which is loosely based on historical events, blends fiction with fantasy through extraordinary 3D images that take advantage of the Play Station 2's highly touted graphics capabilities.

Links DigiWorks brings a samurai battle scene to life (top) with amazing realism for the Onimusha opening game cinematic by incorporating motion-capture data from six actors who were filmed simultaneously with a Vicon 8 system (above).

Capcom wanted the game's opening sequence to be of similar quality, so Links DigiWorks hired Japanese dramatic feature-film director Shimako Sato to help stage the drama. Using a Vicon 8 system, the Links DigiWorks team shot several takes of six actors, specially trained in samurai movements, performing various fighting actions during a four-day motion-capture session. To capture all the motion at once, the group used 12 cameras set up around a 20-meter square area that contained rigs, props, and wooden hills to help depict the terrain where the action occurs in the cinematic sequence. The movements of the props, including spears and other weapons, were also captured during the session.

The most challenging part of the project, according to Ichihashi, was sorting and analyzing the motion data from the 100-plus reflective markers placed on the actors and props. "We had to determine which markers belonged to which characters in the scene, which was an extremely complex process, because the actors were moving around so quickly and hidden by each other's bodies." Once the data was sorted, the group mapped it onto low-resolution Softimage character models for review and additional cleanup of the motion.

Although using motion capture proved arduous-it took nearly eight months to complete just the opening movie-Ichihashi still believes it was the best option. "We chose motion capture over keyframing because we wanted natural, performance-style animation, not Disney-style animation," he says. Also, Ichihashi believes that motion capture will enable the studio to create animation data, particularly for feature films, more quickly and less expensively than they can with keyframing. This project, he estimates, likely would have taken two to three times longer using keyframing.

Creating lifelike motion, however, was only half the battle. To achieve the desired realism for the cinematic, the group needed photo-quality characters on which to map the movements. Using Softimage 3D running on a variety of hardware, they created the main character models, dressed in period clothing and textured with Adobe Systems' Photoshop.

With the company's customized software, the artists also incorporated hordes of warriors and riders on horseback into the animations, as well as special effects such as fog, smoke, and raindrops. "The crowds were especially difficult to control," notes Ichihashi. "At times there were hundreds of people doing battle in the fields." To complete the scenes, the group added backgrounds and non-character models, as well as special effects such as fire and fog using its particle software.

Rendering the sequence, which contains 40 to 50 layers, was done in Softimage, Discreet's 3D Studio Max, and Links DigiWorks' proprietary rendering software, which was used mostly for the effects. According to Ichihashi, the majority of the layers were rendered overnight using a variety of hardware, including SGI machines (O2s, Indys, and Indigo2s), Unix boxes, and NT workstations. Some layers, though, took days to render.

Using Vicon's Body Builder, Links DigiWorks sorted more than 100 mocap markers (left) before mapping the motion to low-resolution Softimage characters for further review (below).

Onimusha: Warlords is expected to receive accolades from the game community, based on the buzz it generated at industry-related shows throughout 2000. But for now, the opening cinematic has been commanding a great deal of attention on its own. This past summer, Links DigiWorks was awarded the Best of Show at the Siggraph 2000 animation festival for its technical and creative achievement in computer animation for the movie sequence.